1. Field of the Invention
This invention relates to a multifunctional printer provided with an energy saver mode that saves power consumption during a standby, a terminal apparatus connected to the multifunctional printer, and a network system provided with the multifunctional printer and terminal apparatus.
2. Description of Related Art
Recently, multifunctional printers are provided with an energy saver mode that controls power consumption within a certain amount when no operation is performed during a preset period. And, there is a need for more power consumption reduction during the energy saver mode.
Conventional facsimile apparatuses (hereafter referred to as FAX) are also provided with energy saver modes and have been considered to have the smallest power consumption during the energy saver mode. The below describes the energy saver mode in a FAX.
A FAX normally includes a main CPU and panel CPU as sub CPU. During a predetermined time period, the FAX monitors whether an operation is performed such as pressing a key. If no operation is performed, the power supply to the main CPU is shut, and only minimum operations are allowed using the sub CPU. Accordingly, only the sub CPU receives the power supply during the energy saver mode, while shutting the power supply to the main CPU, which largely reduces the power consumption down to 1.4 W.
To restore the FAX from the energy saver mode to a ready mode, the sub CPU monitors energy saver cancel factors. When such a factor is detected, the main power switch is turned on to supply the power back to the main CPU. Energy saver canceling factors include an incoming message being detected, a document set, and a key pressed.
However, the above-described technology cannot be applied to a multifunctional printer having a printer function. Therefore, the power consumption of a multifunctional printer during an energy saver mode has been significantly large.
In particular, unlike the energy saver mode of a FAX, it is impossible to shut the power supply to the main CPU during the energy saver mode of a multifunctional printer having a printer function. Instead, the power supply to units that can be turned off, such as fixed parts and scanner, have been shut down while maintaining the power supply to the main CPU.
In a multifunctional printer with a printer function, a printer driver inside a connecting PC has a status monitoring function monitoring the status of the multifunctional printer. Therefore, the PC monitors the status by periodically accessing the multifunctional printer even when the multifunctional printer is in an energy saver mode. The multifunctional printer is required to communicate with the PC to respond to the access from the PC. Since the communication with the PC is performed by starting up a software program, the main CPU has to be started even during the energy saver mode. Therefore, the multifunctional printer cannot shut down the power supply to the main CPU during the energy saver mode, thus consuming much more power approximating from 20 W-30 W during the energy saver mode.
If the multifunctional printer with the printer function shuts down the power supply to the main CPU in order to lower the power consumption during the energy saver mode, the multifunctional printer cannot respond to the status monitoring access from the PC, and the PC misinterprets that the multifunctional printer as a printer is having an error. In this case, the PC misinterprets that the multifunctional printer is having an error every time the multifunctional printer activates an energy saver mode, and keeps sending the wrong message to the user.
Additionally, the multifunctional printer is not only incapable of responding to the status monitoring from PC in this case, but also to a printing request, thereby causing the multifunctional printer to a lose important function as a multifunctional printer.
Further, when the power supply to the main CPU is shut down during the energy saver mode, it is possible to respond to the printing request from the PC and maintain a printer function as a multifunctional printer, if an access from the PC can be included as one of the energy saver cancel factors. However, the status monitoring access from the PC will also be considered as an energy saver cancel factor. Since the status monitoring from the PC is performed periodically, the energy save mode will be canceled frequently, thus practically impairing the energy saver mode.